


Hot Hands, Cold Hearts

by Reddie_Bubb



Category: Undertale (Video Game)
Genre: Alternate Universe - Killertale (Undertale), Alternate Universe - Underswap (Undertale), Comfort/Angst, Ecto-Genitalia (Undertale), Eventual Smut, Killer Sans (Undertale) - Freeform, M/M, Porn With Plot, Underswap Sans (Undertale)
Language: English
Status: Completed
Published: 2020-12-19
Updated: 2021-02-16
Packaged: 2021-03-11 00:21:31
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 1,350
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28176078
Author URL: https://archiveofourown.org/users/Reddie_Bubb/pseuds/Reddie_Bubb
Summary: One day, Blue awoke, feeling unlike himself. He decides to leave his AU, but something happened, causing Killer to find and take care of him. Would they eventually grow on each other? Or would their relationship end off worse than it was? And what about the others? How would their friends and family react if they suddenly disappeared, almost as if they never existed? How will the other two adjust to living in a normal society of monsters, trying their best to make it work?
Relationships: Error/Dream, FluffyNight, Insomnia - Relationship, Killer/Blue, KillerBlue, Nightmare/Ccino
Comments: 4
Kudos: 21





	1. The beginning of our journey..?

**Author's Note:**

> One of my significant others came up with one of the Killer headcanons being used, please ask if you can use it.   
> There's gonna be some gore, fighting, self-harm, and other topics of this nature, viewer discretion is advised!

Blue sighed. Despite how much he tried, there were days his peppy, go get ‘em energy didn't quite show. Today was one of them. He was unable to lie to himself, and he hated it. He hated the constant loop of resets, waking up, and not even knowing what day it was. Not knowing if any of this was real, he had started thinking it was all false.

But that was beside the point. He had to get up. He didn’t want to, but it was out of his control now. He groaned, feeling his bones creaking. Softly as he sat up, his bones popped. He cracked his back and sighed again, not feeling like putting on his usual attire. He stumbled out of his room thirty minutes late, in sweatpants and a baby blue sweater. 

It took him five minutes to set foot into the kitchen, his feet heavy and dragging. He took a deep breath, wandering over to the table and plopping into a chair. He  
looked at the fridge door dully, not feeling like his usual self.

“Mweh...” He was unable to even fake his laugh. He needed a break. He needed a break, and it was very overdue. He huffed, snapping his fingers and summoning a pen to him, writing a quick note to Papyrus. ‘Gone, be back later.’ 

AU hopping was a hobby for him. It allowed him to see all the different realities, showing how every little thing worked in an au. It was soothing almost. He sighed and looked around. The area he was in was beautiful: stars shining brightly above thriving green grass, bright bushes filled with berries and thorns, tall trees with long vines tangled throughout the divots in the trunks, fluorescent flowers scattered across the landscape haphazardly. There was a pond, a dock jutting out over icy gray waters.

Blue sat on the edge of the deck, his feet swinging, gently brushing the still surface with his toes. The water was cold and deep, and he couldn’t see the bottom from his spot. Looking into the small ripples, he reached his hand out.

The surface of the water was enticing, and he gently brushed it with his fingers before realizing how close to the edge of the dock he was. he scrambled back, hitting the edge of a pole. Surprised, he yelped and fell backward, waving his arms frantically to steady himself before falling, painfully hitting the water and falling in. His sweatshirt billowed around him. The flowing water going in and out of his ribcage and through all the hollow areas in his body. His small figure, frozen in shock and cold, dully looked around. The water was stunning. 

Since he was a skeleton, he had no lungs, and therefore no need to breathe. But the cold could kill him, especially since he wasn’t anticipating it. He couldn’t move, he couldn’t speak, call for help. His magic was almost completely gone, and he closed his eye sockets. 

He awoke in a feverish state. His eyes darted around his eye-sockets frantically, his pupils panicked and dilated. He heard a voice, though he couldn’t tell whose it was. They grabbed his chin, not roughly, but not gently either, lifting his face to the light. His vision was fuzzy, and all he could see was their eyes: completely black, mysterious. The room started spinning, his head drooping in their grip before he lost his consciousnesses. He felt himself being gently taken care of while he dozed, his hot body looked after with caution. Medicines and water were carefully put into his mouth, causing him to swallow. He wasn’t sure how long this went on, and he often lost himself in his dreams.

A few days had passed, Killer was worried he wouldn’t make it. “He needs to wake up. I can’t keep him here for much longer, but I can’t leave him without care. I still have some use for him.” He sighed, picking up the smaller, hoisting him up onto his back. “If you won’t wake up, we need to leave. Nightmare is going to be wondering why I have yet to leave my room. It’s high time I escaped anyways, plus the gang would be better off without me. Gotta go now, but I can’t let you leave either.” 

He started talking to Blue as he slept, running a finger over his face, wiping off a bead of sweat. “Nightmare will recognize the residue from me on you. Sorry.” 

He started going around his room, packing things quickly. He grabbed a bag, filling it with clothes, money, and medicine. He also took a set of chiseling tools and his knives. He looked at his former room.

“I'm gonna miss it here. You guys were a family to me", he murmured as hate dripped from his eyes, almost tear-like. His chest heaved, and he wiped his eyes of tears with his sleeves, jotting down a quick note, making sure they knew he was alive and alright. He looked at the letter again, pulling out one of his knives. He stabbed it into the note, leaving a smear of hate on the paper. He then summoned a portal, jumping inside. 

When Blue awoke, it was dark. He tried to sit up, failing miserably. He flopped backward, back onto the bed he was on. He was nowhere near anything he recognized, and he knew that for sure. He scanned the area. The room he was in was beige and black.

The creme-colored duvet was silky and warm against his small body. He noticed his attire had been replaced, his soaked clothing gone. He now wore a comfortable black turtleneck, a red hoodie on top. He wore a pair of new sweatpants, soft fabric hugging him nicely. His eyes widened as Killer walked through his door, glaring at him uncertainly. “What are you doing here?” Killer huffed, his eye-light imperceptibly flickering to life as he did so. ”I'm taking care of you, stupid. Now, are you hungry or some shit?”

The sleeves of his shirt were cuffed, intricately carved, and bloody bones underneath. It looked like he had done the carving himself, yet Blue was unable to ask.

“Hey, I asked you a question-,” Blue snapped out of his slight daze, looking up from his position on the bed. “No, I’m not hungry.” His body was tensed, expecting an attack at any instant. “Calm the fuck down. If I wanted you dead, you would be fucking dead.”

Blue was still tense, and Killer sighed and sat on the edge of the bed, not making any sudden movements.

“Look. I know ya’ don’t trust me. But, we’re here together now. And-“, he looked Blue directly in his eye-sockets as he said this, “We can’t go back to how we were. Not anymore.” He sighed again. “tch... I shouldn't have taken care of you. You’re too much work for your own good, and now we’re stuck in this mess.” Blue glared at him. ”And why should I trust you? You’re a literal murderer, you’ve killed countless monsters, hell, you work for the biggest bad of the multi-“ 

“I don’t work for anyone. Not anymore.”

Blue was slightly shocked, and Killer continued. “We just gotta learn how to adjust to this new world. Cause you and I both know-“, he paused, hooking a finger under Blue’s chin, looking him right in the eyes. 

“Shit is never gonna be the same again. And we gotta stick together from now on.”


	2. I'm sorry-

Hullo-, I wanted to apologize. If you are reading this story, it's discontinued for now. I simply do not have the motivation to continue this half-formed idea. Later on, I may make a little oneshot of this ship, using a bit of the same idea, but for now this idea will be finished. If you wish to write something using this, be my guest. Just link it in the comments, as I would love to read it! I'm currently working on another book, the first chapter of it is underway and coming well, I hope you'll enjoy it!


End file.
